1. Field of the Invention
The present invention relates to a wood type golf club head.
2. Description of the Related Art
In one conventional golf club where a mark for assisting the golfer in having a swing is formed on the club head surface, a straight line that indicates the impact direction, and a straight line in a direction perpendicular to the former straight line are inscribed on the club head surface (Japanese Utility Model Laid-Open No. 5-21976). In the golf club disclosed in Japanese Utility Model Laid-Open No. 5-21976, the above-mentioned mark allows the golfer to easily, correctly address a golf ball in its target impact direction with the club face, and therefore allows him or her to hit the ball in a precise direction.
The head's center of gravity plays an important role in determining the performance of a golf club. The center of weight of the head serves as the center of gravity. Also, a point where a perpendicular line dropped from the center of gravity to the face intersects with the face serves as a sweet spot (the center of gravity corresponding to the face), and a predetermined area with the sweet spot almost as its center serves as a hitting area (sweet area). The lower the center of gravity, the higher a ball easily launches, and the deeper the center of gravity, the larger both the moment of inertia and the sweet area. As can be seen from these and other examples, the center of gravity exerts a great influence on ball trajectory determination and the club's playability.
Hence, to allow the golfer to have a stable swing, it is important for him or her to pay attention to the head's center-of-gravity position at the time of address and swing.
However, since the mark inscribed on the surface of the golf club head disclosed in Japanese Utility Model No. 5-21976 includes a straight line that indicates the impact direction, and a straight line perpendicular to the former straight line, the golfer can pay attention to the impact direction and the face orientation, but cannot pay attention to the head's center-of-gravity position.